The dynamics of the visual system in combining conflicting KDE and binocular stereopsis cues

The dynamics of the visual system in combining multiple depth cues were investigated by measuring the temporal change in the perceived 3-D shape of a random-dot stimulus with conflicting kinetic depth effect (KDE) and binocular stereopsis cues. The KDE shape perception dominated for the first few seconds, and then was gradually supplanted by the stereo shape perception. The effects of various pre-adaptation stimuli suggested that the temporal change in the perceived shape resulted from a self-adaptation of the KDE mechanism that occurs mainly at the levels of motion and relative motion detection.     

Delboeuf “illusions” of circle size induced via photoflash-generated afterimages

Generating an inducing figure by photoflash led to underestimation of the size of a luminous outline test circle in a nonluminous surround. As the afterimage of the inducing circle decayed, judged size of the test circle attained true size. The more intense inducing flash produced a longer lasting perceptible afterimage but no alteration in amount of test-circle underestimation as a function of time. The type of inducing configuration (outer concentric circle, nonconcentric circles, arcs) proved to have no differential effect. In the absence of an inducing figure, subjects make veridical judgments.     

Overextinction of the orienting reaction

Sokolov’s 1963 report of return of the orienting reaction (OR) to repeated stimulus presentations following habituation was examined in 18 S’s using the galvanic skin response (GSR) component of the OR and an auditory stimulus of 60 db intensity and 1000 cps. Both group and individual S data analysis indicated a return of the OR which habituated quickly. The number of stimulus presentations to the OR return point showed an inverse relationship to rate of initial OR habituation for individual S’s.     

Electrocutaneous stimulation III. The perception of temporal order

Temporal order thresholds were measured for brief electrical stimuli presented to the forehead and to the abdomen. Temporal acuity is better (thresholds smaller) on the forehead, sensitivity increasing somewhat (thresholds decreasing) as the physical separation between the electrodes increases. Even in that subject, of four, who had the lowest thresholds, however, the value rarely fell below 100 msec. Temporal order thresholds also depend on the orientation, being far smaller when the electrodes are separated horizontally than when separated vertically on both body sites.     

Are nominal same-different matches slower due to differences in level of processing or to response competition?

Eriksen, O’Hara, and Eriksen (1982) have proposed that the latency advantage ofsame overdifferent judgments when the match is based upon physical identity is due to differential amounts of response competition between the responses by which the judgment ofsame ordifferent is signified. Responses of “different” are slowed by a high level of priming in the competing response signifyingsame. In the present experiment, the response competition model is extended to nominal matches and in particular to what Proctor 1198D has termed the “name-physieal disparity”—a pair of letters are more rapidly judged to have the same name if they are the same ease (e.g., a a) than if they are in different eases (e.g., A a). While response competition effects were found to occur in nominal matches of this kind, the name-physieal disparity was greater than could be attributed solely to response competition. Evidence was obtained that part of the name-physieal disparity could be attributed to the subject’s having two chances to make a-nominal raatch when the letter pair was identical both physically and in name. The match could be made either on the basis of the physical or the name code. It was assumed that name and physical codes were processed at least partially independently.     

A microcomputer-controlled solid-state dark adaptometer

A low-cost microprocessor-controlled light-emitting diode (LED) dark adaptometer is described. The apparent intensities of red and green stimuli are controlled by changing the duty cycles of LED display elements which are operated at constant pulse repetition rates. The psychophysical method of limits is used to obtain threshold data. Stimulus parameters and test procedures are under software control. The design utilizes programmable integrated circuitry that may be used with a variety of microprocessors.     

Processing level and recognition: A search method for inducing alternative encodings of unrelated words

Twenty-four subjects viewed cards containing four words. In synonym orienting, half of the cards contained a synonym pair and half did not; in homophone orienting, half of the displays contained a homophone pair. The remaining two words in each display were used to index retention. During presentation of displays, subjects responded “yes” or “no” to indicate the presence or absence of a matching pair. Following presentation, a recognition test was administered. Half the items were tested early and half were tested late; within each test order, half the items appeared with context cues during testing and half appeared without. Results showed superior recognition (1) following semantic orienting, (2) for items tested early, (3) for items tested with context, and (4) for nonmatch displays requiring exhaustive item comparison. An Orienting by Test Cuing interaction showed that the presence of test cues improved recognition for homophone orienting items only. The interaction may have resulted from the lack of cuetarget associations and the reinstatement of the phonemic orienting set during the test.     

The solution of anagrams: A reexamination of the effects of transition letter probabilities,letter moves,and word frequency on anagram difficulty

Word frequency (WF), number of letter moves, and solution word transition letter probabilities (TP) were related to anagram solution. The solution word TP measure was based on the relative frequencies of correct to incorrect bigrams within the pool of bigrams defined by the letters of the anagram rather than on the absolute frequencies of the correct bigrams. This bigram rank measure, which also took word length and letter position into account, was a powerful predictor of anagram difficulty (p < .001). Likewise, number of letter moves predicted anagram solution strongly (p < .001), but WF was only a marginal predictor (.05 < p < .10). In addition, there were no significant interactions among the three variables, nor wasanagram TP consistently related to anagram difficulty. The results were interpreted in terms of an approach which combined elements of an hypothesis and an S-R mediational theory.     

The effect of interstimulus procedures on salt taste intensity functions

Taste intensity functions were constructed for the salt taste, using variations of the method of direct magnitude estimation, to study the effects of adaptation to residuals from prior tastings. The prediction that mouthrinsing would reduce residuals, lower the level of adaptation, and thus yield lower exponents was confirmed. The effect of the residuals tended to be reduced, tiowever, when the power functions were adjusted for such threshold changes. Power function deviations from linearity were also discussed. The literature on intensity scaling for the salt taste was examined and seen to support these findings. It was concluded that the interstimulus procedure, by altering residual stimulus levels, played a major role in determining salt taste intensity functions.     

The effect of interstimulus procedures

NaCl detection and recognition thresholds were measured with and without a prior artificial raising of the level of adaptation by a molar salt mouthrinse. In both cases, it was found that an interstimulus procedure involving water mouthrinses yielded lower thresholds than a procedure with no rinses. These results were seen to be predicted from adaptation level changes. The literature was seen to confirm these results, while difficulties in threshold measurement were discussed.